Democrats are drooling over the possibility of retaking not just the House, but the Senate too. But their own foolishness may cost them a decent chance at the upper chamber.

The field is already slanted heavily against them. There are 35 Senate seats up for election on Nov. 6, and Democrats hold 26 of them. Making matters worse, many of these Democrats are up for re-election in red states that President Trump won (like North Dakota, West Virginia, and Missouri) — though there are unexpectedly tight races in Texas and Tennessee that might give Democrats a countervailing edge. Add to that President Trump's dismal approval ratings and the Democrats' mammoth lead in generic congressional polls, and it seems like there should be a decent chance that they run the table and take the Senate.

There's a big problem though: scandal-stained Sen. Bob Menendez (D-N.J.) and his long history of outrageous corruption.

Democrats could have ditched this turkey for virtually any other person in the state and cruised to victory. Instead, top Democrats like Senate Minority Leader Chuck Schumer (D-N.Y.) and Sen. Cory Booker (D-N.J.) protected and enabled him.

Polling is now nearly tied between Menendez and his Republican challenger Bob Hugin. Some 59 percent of New Jersey voters say Menendez's corruption scandal is "extremely important" or "significant" in their vote. It's an object lesson in the political dangers of letting moral rot slide.

Menendez allegedly helped a crooked doctor named Salomon Melgen commit Medicare fraud on a massive scale. Melgen was convicted of stealing $73 million from the program by forcing his patients to undergo unnecessary (and sometimes excruciating) medical procedures. As Glenn Greenwald details, he buttered up Menendez with $600,000 in campaign donations, a luxury hotel stay in Paris, multiple free trips on a private jet, and other gifts. In return, the senator apparently interceded with the government on Melgen's behalf, trying to get payment disputes resolved in his favor.

Menendez was prosecuted for corruption over this, which ended in a hung jury last year. (Melgen was later convicted of fraud and sentenced to 17 years in prison.) In the corruption trial, the facts of the matter were not in dispute, only the reason for them happening. As I've written before, conservatives on the Supreme Court have slowly cored out anti-corruption law by raising a ludicrous standard of proof. Basically, you can marinate in corruption until your heart shrivels up like a raisin, so long as you don't notarize the words "I'm taking these gifts and money, and in return I will illegally grant you political favors." Menendez was never quite that stupid, and so avoided conviction — though he was censured by the Senate.

As Alex Pareene points out, for a time Democrats hung on to Menendez because they had the excuse of Republican Chris Christie in the New Jersey governor's seat (who would make the appointment to replace Menendez). But Democrat Phil Murphy replaced Christie many months ago. Democrats still did not move to get rid of Menendez. On the contrary, the entire New Jersey Democratic machine — which is very nearly as corrupt as that of New York state, and that is saying a lot — circled the wagons around Menendez.

The state Senate president, the incoming Assembly speaker, Booker, Murphy, and all the other top New Jersey Democratic barons endorsed Menendez. More importantly, they refused to fund any other candidate, thus prompting his sole significant primary challenger, former Clinton and Obama staffer Michael Hopkins, to drop out for lack of funds. Meanwhile, Schumer let Menendez take his spot back as the top Democrat on the Foreign Relations Committee (where he is an appalling neocon mini-me) as soon as he skated on the charges.

Alas, Hopkins very probably could have won if he had simply stuck it out and scraped by with grassroots funding, as Menendez barely cracked 60 percent in the primary against a totally unknown community newspaper publisher named Lisa McCormick with no money or connections.

The anti-Menendez vote is strong, as people have understandable reluctance to vote for such a nakedly corrupt guy — as we are finding out today, with a Republican running neck-and-neck in a state Hillary Clinton won by 14 points, and in a cycle with enormous anti-GOP hostility.

However, narrow tactical political questions aren't the only problem here. Protecting and enabling a crooked pol also makes it that much harder to run against GOP corruption generally, whether it's that of President Trump or any of the other Republicans under a cloud of scandal or literal indictment. A Democratic Party concerned with national victory would maintain high ethical standards at least out of a cynical desire to claim the moral high ground over Trump's awesome sludge of corruption, and give Menendez the boot. (Also being corrupt is, you know, morally wrong.)

But instead they protected their good old boy friend, Hugin has a very strong electoral argument, and Republican propaganda outlets are gleefully trumpeting every new wrinkle in the story. And it just might cost the Democrats control of the Senate. Idiots.